trichome

Trichomes are fine outgrowths or appendages on plants and certain protists. These are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae.

Trichomes on plants are epidermal outgrowths of various kinds. The terms emergences or prickles refer to outgrowths that involve more than the epidermis. This distinction is not always easily applied. Also, there are nontrichomatous epidermal cells that protrude from the surface. 

A common type of trichome is a hair. Plant hairs may be unicellular or multicellular, branched or unbranched. Multicellular hairs may have one or several layers of cells. Branched hairs can be dendritic (tree-like), tufted, or stellate (star-shaped).

A common type of trichome is the scale or peltate hair: a plate or shield-shaped cluster of cells attached directly to the surface or borne on a stalk of some kind.

Any of the various types of hairs may be glandular.